As a technique for introducing an impurity to a surface of a solid-state sample, a plasma doping method has been known in which an impurity is ionized and the ionized impurity is introduced to a solid-state material at low energy (for example, see Patent Document 1).
FIG. 24 shows a schematic structure of a plasma processing device used for a plasma doping method serving as a conventional impurity-introducing method described in Patent Document 1. In FIG. 24, a sample electrode 202 on which a sample 201 made of a silicon substrate is placed is provided in a vacuum container 200. A gas supply device 203 for supplying a doping material gas containing a desired element, such as B2H6, and a pump 204 for reducing the pressure of the inside of the vacuum container 200 are provided in the vacuum container 200 so that the inside of the vacuum container 200 can be maintained at a predetermined pressure. A microwave is projected into the vacuum container 200 through a quartz plate 206 serving as a dielectric window by a microwave waveguide tube 205. By an interaction between this microwave and a DC magnetic field formed by an electromagnet 207, a microwave plasma 208 with a magnetic field (electron cyclotron resonance plasma) is formed in the vacuum container 200. A high-frequency power supply 210 is connected to the sample electrode 202 with a capacitor 209 interposed therebetween so as to control the electric potential of the sample electrode 202. Here, a gas to be supplied from the gas supply device 203 is supplied into the vacuum container 200 through a gas blowing hole 211, and exhausted into the pump 204 from an exhaust outlet 212.
In the plasma processing device having this structure, the doping material gas, for example, B2H6, introduced from the gas blowing hole 211, is formed into plasma by a plasma generating means configured by the microwave waveguide tube 205 and the electromagnet 207 so that boron ions in the plasma 208 are introduced into the surface of the sample 201 by the high-frequency power supply 210.
After a metal wiring layer has been formed on the sample 201 to which an impurity is thus introduced, a thin oxide film is formed on the metal wiring layer in a predetermined oxidizing atmosphere, and a gate electrode is then formed on the sample 201 by a CVD device or the like so that, for example, an MOS transistor is obtained.
Patent Document 2 and Patent Document 6 have disclosed a technique in which a substance 223 containing an impurity is preliminarily adhered to an inner wall face of a vacuum container 222 of a dielectric window 221 of an ICP plasma device 220 as shown in FIG. 25, and by introducing a nitrogen, helium or argon gas into the vacuum container 222, a plasma is generated in the vacuum container 222 so that the impurity is introduced into a semiconductor.
In this method, the substance 223 containing an impurity, such as arsenic, phosphorus, or boron, is preliminarily adhered to an inner wall face of the dielectric window 221, and by forming a nitrogen, helium, or argon gas into a plasma inside the vacuum container 222, the substance 223 containing the impurity, adhered to the inner wall face of the dielectric window 221, is sputtered, and this is used as a material and introduced into the silicon substrate 224. Moreover, another method using the similar structure has been proposed in which a dielectric window having an inner wall to which a substance containing an impurity is preliminarily adhered is arranged in a helicon-wave plasma device or a magnetic neutral loop plasma device, in which, in place of a coil 225, an antenna and an electromagnet serving as a magnetic-field forming device are used, so that a plasma doping process is carried out.
Patent Document 3 has disclosed a plasma doping method that uses a plasma doping apparatus as shown in FIG. 26 to form an impurity-introduced layer on a substrate to be processed, and is provided with step (a) for preparing a vacuum container 230 having an inner wall on which a film 231 containing a first impurity has been formed; step (b) in which, after the step (a), the substrate 234 to be processed is placed on the sample base 232; step (c) in which, after the step (b), a plasma containing a second impurity is generated in the vacuum container 230 with high-frequency power being supplied to an electrode made from the sample base 232, so that the first impurity and the second impurity are introduced into the substrate 234 to be processed to form the impurity introducing layer. This method is a modified method obtained from those of Patent Document 1, Patent Document 2, and Patent Document 6, and is devised by newly taking it into account that, when a plasma doping process is carried out by using an ICP plasma device as shown in FIG. 25, a film containing an impurity is formed on the inner wall of the vacuum container during the process with a very large amount of the impurity being generated from the film. By utilizing this fact, Patent Document 3 has achieved superior in-plane uniformity and reproducibility of the dose amount that have not been obtained by a conventional plasma doping process by adjusting the sum of the amounts of the first impurity derived from the film containing the impurity, which has not been taken into account in the conventional plasma doping process, and the second impurity contained in plasma, which has been taken into account in the conventional plasma doping process.
Moreover, FIGS. 1, 5, and 6 of Patent Document 4 have proposed a sputtering electrode in which a target to be sputtered by plasma has a shape similar to an annular shape (a shape having a concave portion in the center), in a sputtering device as shown in FIG. 27.
Furthermore, in FIG. 12, Patent Document 5 has disclosed a device that supplies a gas from a micro-nozzle placed opposing to the substrate toward the substrate in a manner like a shower.    Patent Document 1: U.S. Pat. No. 4,912,065    Patent Document 2: JP-A No. 2004-047695    Patent Document 3: WO/2006/121131    Patent Document 4: JP-A No. 61-183467    Patent Document 5: JP-A No. 2005-5328    Patent Document 6: US. Patent Application A1 Laid-Open No. 2004/0045507